I currently own a BMW 325i Sedan(E90) and it never gave me any troubles. *touchwood*

Recently, I am considering to purchase a 335i Coupe. I've went to the showroom last night and there was one nice black one but it is a 2009 model with a nice discounted price tag. As I have heard the 2010 models, now I am confused whether to get this demo car or not.

Can someone give me some advice whether it's worth it to get this demo car?

As far as I know there really aren't any major changes between the 09's and the 10's. If the price is right and you really want it I'd go for it. The N54B30 is a sweet motor and I know for a fact that it can rocket an E92 coupe down the road effortlessly.